Glenn Ashmore wrote:

I would be real interested inknowing how you would apply 1/4 oz of MEKP
to 6 or 8 square feet of cloth. ;-)

I use polyester for molds and things like shower basins and grey water
tanks but compared to epoxy it is a PITA. A quart of resin requires
something between 5 to 10 ml of MEKP depending on the temperature, the
hunidity and the phase of the moon. A ml to much and it turns to gum
before you can get the glass laid tight. If you don't mix it extremely
well it forms jelly beans in the pot. If you are an ounce short you
still have to mix a pint because it is almost impossible to measure that
small amount of MEKP.

With epoxy you just get a squirt of resin and a squirt of hardner and
you have about half an ounce. If it is hot you use a slow hardner. If
it is nice out you use a normal harnder. If it is cold you use a fast
hardner. But it is always a squirt of each.

IF you need a lot the hardware store sell graduated mixing pots for
about $.75 that are good for several sessions.

IF you don't glas very often, epoxy has a shelf life measured in years.
I have never had a can of polyester make it past 9 months after it is
opened.


Absolutely.

I've done a bit of aircraft fiberglass work, but I've bever built a
glass hull.
http://home.flash.net/~lamb01/cowl.htm

I use large syringes from the vet for mixing.
My resin mix is 6:1 by volumn.
60cc of resin in the big shot.
10 cc of hardner in the little one.
Its easy to double that with two shots of each.
But that's about as much resin as I mix in one cup.
For large layups, I premix 140cc in baggies and put them in the fridge.

I don't mean to step on any toes, but since this is a boat building
forum...

West is a commonly recognized epoxy but imho West is NOT a sutable
laminating
resin for making fiberglass parts.
It's fabulous with wood.
But the mechanical properties are low and glass parts tend to be
brittle.

I've used Dow 330 for years, but can't get it any more.
Now I mostly use AeroPoxy.

There are several inexpensive laminating resins listed in Aircraft
Spruce.
There are some expensive resins listed too!

Glassing wood? West is best.
But for glass or carbon parts, there are much better resins.


Richard

Just my opinion, I could be wrong.

Richard Lamb wrote:

I don't mean to step on any toes, but since this is a boat building
forum...

West is a commonly recognized epoxy but imho West is NOT a sutable
laminating
resin for making fiberglass parts.
It's fabulous with wood.
But the mechanical properties are low and glass parts tend to be
brittle.

I've used Dow 330 for years, but can't get it any more.
Now I mostly use AeroPoxy.

There are several inexpensive laminating resins listed in Aircraft
Spruce.
There are some expensive resins listed too!

Glassing wood? West is best.
But for glass or carbon parts, there are much better resins.


That is correct. That is also why West has a sister line called Pro-Set
which is a laminating epoxy.

--
Glenn Ashmore

I'm building a 45' cutter in strip/composite. Watch my progress (or lack
there of) at: http://www.rutuonline.com
Shameless Commercial Division: http://www.spade-anchor-us.com

Glenn Ashmore wrote:

Richard Lamb wrote:

I don't mean to step on any toes, but since this is a boat building
forum...

West is a commonly recognized epoxy but imho West is NOT a sutable
laminating
resin for making fiberglass parts.
It's fabulous with wood.
But the mechanical properties are low and glass parts tend to be
brittle.

I've used Dow 330 for years, but can't get it any more.
Now I mostly use AeroPoxy.

There are several inexpensive laminating resins listed in Aircraft
Spruce.
There are some expensive resins listed too!

Glassing wood? West is best.
But for glass or carbon parts, there are much better resins.


That is correct. That is also why West has a sister line called Pro-Set
which is a laminating epoxy.

--
Glenn Ashmore

I'm building a 45' cutter in strip/composite. Watch my progress (or lack
there of) at: http://www.rutuonline.com
Shameless Commercial Division: http://www.spade-anchor-us.com


Thanks.
Haven't seen that one on the shelves tho.
Mostly just West 105.

Hey Richard, just out of curiosity for the polyester crowd, how many
aircraft builders, hobby and commercial do you know of that ust
polyester?

regards, Ron

I don't recieve e-mail at this address because of spam. E-mail me
at crtsrATmsnDOTcom.

Ron Thornton wrote:

Hey Richard, just out of curiosity for the polyester crowd, how many
aircraft builders, hobby and commercial do you know of that ust
polyester?

regards, Ron

I don't recieve e-mail at this address because of spam. E-mail me
at crtsrATmsnDOTcom.

Not a single one anymore...

Even most of the kit manufacturers have changed over to epoxy.

OTOH, there is a growing use of vinyl ester resin.
It is catalized and works a lot like polyester, but with better
chemical resistance and much better physical properties.

Richard

It should be recognized that compared to boat builders, the airplane crowd
really throws money at a project. (Yeah, I know it is hard to believe there is
an easier way to dispose of excess funds than boating.) The cost of epoxy
over polyester is really not a major factor.

While a Sevtec surface effect vehicle (or sev) may cost the builder about $4000
minus for a 4 place, 30mph over water 25hp garden tractor engined machine, the
airplane builders spend maybe $40,000 and way up, more than half of that
sometimes just on the engine.

Also, skins on aircraft are very light, you cannot walk on them. Boats must
have a much more substantial build, due to this and vastly higher point and
overall loading, so the quantity of resin is far more significant. (Sevtec
does use vinyl ester resin on a manufactured craft, though, primarily as it is
claimed (though maybe not proven) that moisture penetration is less than
cheaper resins. Of course, boats use epoxy for the same reason, maybe a single
coat near at and below the waterline.


Subject: Polyester or Epoxy?
From: Richard Lamb
Date: Sat, Jan 17, 2004 11:10 AM
Message-id:

Ron Thornton wrote:

Hey Richard, just out of curiosity for the polyester crowd, how many
aircraft builders, hobby and commercial do you know of that ust
polyester?

regards, Ron

I don't recieve e-mail at this address because of spam. E-mail me
at crtsrATmsnDOTcom.

Not a single one anymore...

Even most of the kit manufacturers have changed over to epoxy.

OTOH, there is a growing use of vinyl ester resin.
It is catalized and works a lot like polyester, but with better
chemical resistance and much better physical properties.

Richard

BRBR


Barry Palmer, for A
HREF="http://members.aol.com/sevtec/sev/skmr.html"Sevtec/A

Dunno aboput that, Barry.
My new plane cost me about $6k US.
But then I made most all of the parts rather than
buying parts. Makes a difference.

Richard

Barry Palmer wrote:

It should be recognized that compared to boat builders, the airplane crowd
really throws money at a project. (Yeah, I know it is hard to believe there is
an easier way to dispose of excess funds than boating.) The cost of epoxy
over polyester is really not a major factor.

While a Sevtec surface effect vehicle (or sev) may cost the builder about $4000
minus for a 4 place, 30mph over water 25hp garden tractor engined machine, the
airplane builders spend maybe $40,000 and way up, more than half of that
sometimes just on the engine.

Also, skins on aircraft are very light, you cannot walk on them. Boats must
have a much more substantial build, due to this and vastly higher point and
overall loading, so the quantity of resin is far more significant. (Sevtec
does use vinyl ester resin on a manufactured craft, though, primarily as it is
claimed (though maybe not proven) that moisture penetration is less than
cheaper resins. Of course, boats use epoxy for the same reason, maybe a single
coat near at and below the waterline.

Subject: Polyester or Epoxy?
From: Richard Lamb
Date: Sat, Jan 17, 2004 11:10 AM
Message-id:

Ron Thornton wrote:

Hey Richard, just out of curiosity for the polyester crowd, how many
aircraft builders, hobby and commercial do you know of that ust
polyester?

regards, Ron

I don't recieve e-mail at this address because of spam. E-mail me
at crtsrATmsnDOTcom.

Not a single one anymore...

Even most of the kit manufacturers have changed over to epoxy.

OTOH, there is a growing use of vinyl ester resin.
It is catalized and works a lot like polyester, but with better
chemical resistance and much better physical properties.

Richard

BRBR

Barry Palmer, for A
HREF="http://members.aol.com/sevtec/sev/skmr.html"Sevtec/A

This is an epoxy plane? My first "plane" cost me $10.98, 1960 prices, it would
be much higher in 2004 dollars. Look at the Sevtec website and follow the
links. No epoxy or polyester was in ght, and I used a free engine, gravity.

Subject: Polyester or Epoxy?
From: Richard Lamb
Date: Sat, Jan 17, 2004 4:27 PM
Message-id:

Dunno aboput that, Barry.
My new plane cost me about $6k US.
But then I made most all of the parts rather than
buying parts. Makes a difference.

Richard
BRBR

Barry Palmer, for A
HREF="http://members.aol.com/sevtec/sev/skmr.html"Sevtec/A

Well we all hear quite a bit about the evils and wonders of both
polyester and epoxy. But what about vinylester? Any one ever use
that? I'm curious because
I saw a vinylester/kevlar canoe prototype by Mad River Canoes that was
20 years old, light as a feather and showed hardly a scratch though it
had been dragged through gravel for years
SteveJ


Richard Lamb wrote in message ...
Ron Thornton wrote:

Hey Richard, just out of curiosity for the polyester crowd, how many
aircraft builders, hobby and commercial do you know of that ust
polyester?

regards, Ron

I don't recieve e-mail at this address because of spam. E-mail me
at crtsrATmsnDOTcom.

Not a single one anymore...

Even most of the kit manufacturers have changed over to epoxy.

OTOH, there is a growing use of vinyl ester resin.
It is catalized and works a lot like polyester, but with better
chemical resistance and much better physical properties.

Richard

SteveJ wrote:

Well we all hear quite a bit about the evils and wonders of both
polyester and epoxy. But what about vinylester? Any one ever use
that? I'm curious because
I saw a vinylester/kevlar canoe prototype by Mad River Canoes that was
20 years old, light as a feather and showed hardly a scratch though it
had been dragged through gravel for years
SteveJ


well, in aircraft, Vinyl ester has become popular as a replacement
for polyester. One of the chief benefits is that vinyl ester is
not affected by the many solvents in auto gas. Polyester and many
epoxies will leach out in time and start leaking. That's considered
a bad thing, usually...

Richard